Basically, you need to learn how uboot works, and how to use the uEnv.txt
file. I wrote up a blog about booting from USB here:
http://www.embeddedhobbyist.com/debian-tips/beaglebone-black/beaglebone-black-usb-boot/

Passed this, uboot has the "boot round robin check" hard coded in. Which I
am pretty sure could be changed before recompiling.


On Mon, Apr 21, 2014 at 5:36 AM, Gerald Coley <[email protected]>wrote:

> My suggestion, and it is just a suggestion, would to read the System
> Reference Manual.
>
> http://www.elinux.org/Beagleboard:BeagleBoneBlack
>
>
> Gerald
>
>
>
> On Sun, Apr 20, 2014 at 10:17 AM, <[email protected]> wrote:
>
>> Hi, I want to change the boot order of the beaglebone black to USB disk->
>> eMMC->others. What topics should I study? I also want to remove the boot
>> button. I want it such that whenever the U-Boot would search in the USB for
>> linux image.
>>
>> Thanks.
>>
>>
>> On Tuesday, October 29, 2013 10:21:09 PM UTC+8, Gerald wrote:
>>
>>> Correct. Unless you want to change the boot mode.
>>>
>>> Gerald
>>>
>>>
>>>
>>> On Tue, Oct 29, 2013 at 9:05 AM, <[email protected]> wrote:
>>>
>>>> So I should not input high,low either .
>>>> I undertood. Thank you.
>>>>
>>>> 2013年10月28日月曜日 22時14分01秒 UTC+9 Gerald:
>>>>>
>>>>> A. The pins cannot float. They are already terminated on the board,
>>>>> either hi or lo.
>>>>>
>>>>> Gerald
>>>>>
>>>>>
>>>>>
>>>>> On Sun, Oct 27, 2013 at 9:46 PM, <[email protected]> wrote:
>>>>>
>>>>>> Hi,
>>>>>> Please tell me about correct circuitry to use boot pins as input,
>>>>>>
>>>>>> I use Beaglbone Black and want to use these pins,
>>>>>> especially eQep counter pins P8-33,35,41,42 that match to SYS_BOOT
>>>>>> 4,5,12,13.
>>>>>>
>>>>>> In SRM (ver A6) p104 it says,
>>>>>> "If you plan to use any of these signals, then on power up, these
>>>>>> pins should not be driven."
>>>>>>
>>>>>> Which of below is correct circuitry?
>>>>>> A) Attach pins to ground until SYS_RESETn goes high.
>>>>>> B) Keep pins floated until SYS_RESETn goes high.
>>>>>>
>>>>>> A is easier, because it can be done by switching 1 relay pulling all
>>>>>> pins to ground.
>>>>>> For B, I need plenty relays.
>>>>>>
>>>>>> Thanks,
>>>>>> Tohru
>>>>>>
>>>>>>
>>>>>> 2013年4月12日金曜日 4時20分23秒 UTC+9 DarkHelmet:
>>>>>>
>>>>>>> You can absolutely use them for other usages, once the value has
>>>>>>> been latched at boot they can be re purposed  It may be necessary
>>>>>>> to strengthen the pull up/down on those lines with external resistors
>>>>>>> though. I've encountered an issue where my TTL inputs were pulling the
>>>>>>> lines low at boot while the CPU latched the config, preventing it to 
>>>>>>> boot
>>>>>>> from the correct configuration. Resistors of ~50k seem to do the trick.
>>>>>>>
>>>>>>> On Friday, April 5, 2013 6:04:18 AM UTC-4, [email protected] wrote:
>>>>>>>>
>>>>>>>> Hi,
>>>>>>>>
>>>>>>>> I've a beaglebone with the XAM3359Z0Z,
>>>>>>>>
>>>>>>>>
>>>>>>>> I discovered that there is 19 pins dedicated to the boot
>>>>>>>> configuration.
>>>>>>>> The documentation said that depending of the position of the
>>>>>>>> switch, The beaglebone will boot with the sd card, uart, ..... .
>>>>>>>> ( http://processors.wiki.ti.com/index.php/AM335X_StarterWare
>>>>>>>> _Booting_And_Flashing#Boot_Modes)
>>>>>>>>
>>>>>>>>
>>>>>>>> I wanted to know if it is possible to use these pins for an another
>>>>>>>> usage? How ? I don't need an another boot mode, the default one is 
>>>>>>>> enough
>>>>>>>> for me.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Thank you in advance for your help,
>>>>>>>>
>>>>>>>  --
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>>>>>
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